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// Copyright 2021-2022 Zenlink.
// Licensed under Apache 2.0.

#![allow(clippy::type_complexity)]

use codec::{Decode, Encode};
use scale_info::TypeInfo;
use serde::{Deserialize, Serialize};

use super::*;

#[derive(Serialize, Deserialize, Encode, Decode, Eq, PartialEq, Copy, Clone, PartialOrd, Ord, TypeInfo)]
#[serde(rename_all = "camelCase")]
pub struct PairInfo<AccountId, AssetBalance, AssetId> {
    pub asset_0: AssetId,
    pub asset_1: AssetId,

    pub account: AccountId,
    pub total_liquidity: AssetBalance,
    pub holding_liquidity: AssetBalance,
    pub reserve_0: AssetBalance,
    pub reserve_1: AssetBalance,
    pub lp_asset_id: AssetId,
    pub status: u8,
}

impl<T: Config> Pallet<T> {
    pub fn supply_out_amount(supply: AssetBalance, path: Vec<T::AssetId>) -> AssetBalance {
        Self::get_amount_out_by_path(supply, &path).map_or(AssetBalance::default(), |amounts| {
            *amounts.last().unwrap_or(&AssetBalance::default())
        })
    }

    pub fn desired_in_amount(desired_amount: AssetBalance, path: Vec<T::AssetId>) -> AssetBalance {
        Self::get_amount_in_by_path(desired_amount, &path).map_or(AssetBalance::default(), |amounts| {
            *amounts.first().unwrap_or(&AssetBalance::default())
        })
    }

    pub fn get_estimate_lptoken(
        asset_0: T::AssetId,
        asset_1: T::AssetId,
        amount_0_desired: AssetBalance,
        amount_1_desired: AssetBalance,
        amount_0_min: AssetBalance,
        amount_1_min: AssetBalance,
    ) -> AssetBalance {
        let sorted_pair = Self::sort_asset_id(asset_0, asset_1);
        match Self::pair_status(sorted_pair) {
            Trading(metadata) => {
                let reserve_0 = T::MultiCurrency::free_balance(asset_0, &metadata.pair_account);
                let reserve_1 = T::MultiCurrency::free_balance(asset_1, &metadata.pair_account);
                Self::calculate_added_amount(
                    amount_0_desired,
                    amount_1_desired,
                    amount_0_min,
                    amount_1_min,
                    reserve_0,
                    reserve_1,
                )
                .map_or(Zero::zero(), |(amount_0, amount_1)| {
                    Self::calculate_liquidity(amount_0, amount_1, reserve_0, reserve_1, metadata.total_supply)
                })
            }
            _ => Zero::zero(),
        }
    }

    pub fn get_pair_by_asset_id(
        asset_0: T::AssetId,
        asset_1: T::AssetId,
    ) -> Option<PairInfo<T::AccountId, AssetBalance, T::AssetId>> {
        let pair_account = Self::pair_account_id(asset_0, asset_1);
        let lp_asset_id = Self::lp_asset_id(&asset_0, &asset_1)?;

        let status = match Self::pair_status(Self::sort_asset_id(asset_0, asset_1)) {
            Trading(_) => 0,
            Bootstrap(_) => 1,
            Disable => return None,
        };

        Some(PairInfo {
            asset_0,
            asset_1,
            account: pair_account.clone(),
            total_liquidity: T::MultiCurrency::total_issuance(lp_asset_id),
            holding_liquidity: Zero::zero(),
            reserve_0: T::MultiCurrency::free_balance(asset_0, &pair_account),
            reserve_1: T::MultiCurrency::free_balance(asset_1, &pair_account),
            lp_asset_id,
            status,
        })
    }

    /// Calculate the underlying amounts for burning LP tokens using
    /// the formula (lp_balance * reserve) / lp_total_supply
    pub fn calculate_remove_liquidity(
        asset_0: T::AssetId,
        asset_1: T::AssetId,
        amount: AssetBalance,
    ) -> Option<(AssetBalance, AssetBalance)> {
        let pair_account = Self::pair_account_id(asset_0, asset_1);
        let lp_asset_id = Self::lp_asset_id(&asset_0, &asset_1)?;
        let lp_total_supply = T::MultiCurrency::total_issuance(lp_asset_id);

        Some((
            Self::calculate_share_amount(
                amount,
                lp_total_supply,
                T::MultiCurrency::free_balance(asset_0, &pair_account),
            ),
            Self::calculate_share_amount(
                amount,
                lp_total_supply,
                T::MultiCurrency::free_balance(asset_1, &pair_account),
            ),
        ))
    }
}